Below are 2 slides from a presentation by Tom Mathews, based on the peer-reviewed article by him and others, "Mortality impacts of the most extreme heat events", in Nature Reviews Earth and Environment. Feb. 4, 2005
The dark red areas are viewed as uninhabitable, at 2.7°C warming (about 1.3°. from now)
As Earth continues warming, more of it will become too hot and humid for humans to survive very long. That portion now is very small - bits around the Persian Gulf and some other tropical coasts on some summer afternoons. But it will grow.
Heat stroke damages the brain & other organs. It kills 10% of victims. It often follows heat cramps, fainting, or heat exhaustion. U.S. heat stroke rates were highest in Arizona (1.7 deaths per 100,000), Nevada (1.0) and Missouri (0.8).
When conditions are too humid and hot, the body can no longer cool itself by sweating. Heat stroke can follow quickly.
Heat Is Testing the Limits of Human Survivability. Here’s How It Kills. 0724.rtf
Maps below show number of days with a wet-bulb temperature > 31°C [88°F],
for future global temperatures: 1.5, 2, 3, and 4°
This > 31°C day-night average is difficult to survive for days on end.
Highest THI (95-100°F) is in S TX & E Baja. THI 90-95°F in FL panhandle, SE of Yuma AZ & 40% of TX. Some Category II (FL, some GA-AL-MS & AZ, most of TX), but no Category III (105-129°F) in the US this day. Category III (THI 105-115°F) ocurred after noon.
Playgrounds are dangerous, even very dangerous, in the heat
Extreme Heat Will Change Us 1222.rtf - health, adaptation, inequality, the future - The story compares laborers and other people in Kuwait and Basra, Iraq. Kuwaiti citizens (but not laborers). Most Kuwaitis avoid going outside. Air conditioning is a rare luxury in Basra (Garden of Eden land), where it got to 164°F on the welder's benchtop and 179°F on a tire swing on a playground. The struggle to sweat and cool off increases risk of kidney stones and kidney disease. The welder's body temperature rose 3°C, a dangerous fever, from the outdoor heat. Chronic dehydration abounds in Basra.
35°C wet-bulb temperature (gray) is lethal. It depends highly on relative humidity.
Too Hot to Live - Millions Worldwide Will Face Unbearable Temperatures 0621.rtf
- A MUST read: long, detailed and wide-reaching.
Potentially Fatal Combinations of Humidity and Heat Emerging across the Globe 0520.rtf - take 2.
See wet bulb temperatures. At the original URL (here), zoom in and out for more detail, including all place names, dates, and wet bulb termperatures recorded. Using hourly data insteada of daily average data, it appears that 10 places have already equalled or exceeded the 35°C threshold of human survivability (lethal wet bulb temperature). These include 3 in Mexico, 2 each in Saudi Arabia and Pakistan, and 1 each in India, Australia, and Venezuela. A wet-bulb temperature calculator is here.
Surge In ‘Danger Days’ Just around the Corner 0815.rtf
Portland, ME, Flint, MI & Rochester, NY are set to each go from 0 danger days to more than 60 / year by 2050.
Days above 95°F will roughly triple. (See Figure 1, partly excerpted above.) This includes 75-100 such days a year for southern Illinois (Carbondale, Cairo, Vincennes, plus Decauter) and more than half of Missouri (St. Louis, Cape Girardeau, Joplin, Sedalia, Rolla, Poplar Bluff, Hannibal, etc.) It also includes Evansville IN and sliver of Ohio between Portsmouth and Marietta and Iowa north of Hannibal. This is almost as hot as Las Vegas.
The Midwest in particular will experience rising temperatures, in terms of warmer winters more than unbearable summers. But by the end of the century, the average Midwesterner will likely see 22 to 77 days per year over 95°F, compared to only 3, on average, over the past 30 years.
There is a 5% (or more) chance that 125-150 days a year will exceed 95°F in much the same area (plus Terre Haute and Jasper IN and Effingham IL, but minus Hannibal and Sedalia MO). See the rest of Figure 1 in the report.
These compare to 114 days above 95°F for Las Vegas in 2014, 95 such days in 2013, and 115 in 2012. The southern Midwest can become hotter than Las Vegas by the end of the century (or a little later), if current emission trends continue.
Below at right, Category II probably corresponds to green in the colored table above (THI 90-104°F), Category III to yellow (105-129°F), and Category IV to red (130°F +).
Below, based on current emission trends (maps from Figure 3 in the report), summers in Missouri, Illinois, and Indiana grow hotter by 2100 than Texas and Arizona ones today. Iowa and Ohio ones grow as hot as Texas ones now. Michigan, Minnesota and Wisconsin summers grow almost as hot.
At right, heat stroke days will increase dramatically by the end of the century, from none now. Most of Missouri, Illinois and Indiana would suffer 40-60 days a year of dangerous heat: as bad (hot and humid) as anywhere in Texas. Ohio and Iowa would see 30-50 such days a year.
Worse, all of Illinois - and most of Missouri, Iowa, and Indiana - would experience 10-25 days a year of extremely dangerous heat: hotter (wet bulb) than anywhere in Texas.
In fact, “On our current path, the Midwest will likely see an average of as many as 3 days per year of Category IV conditions, which have never been experienced in the U.S. to date.”
Section Map: Bio Impacts